Rubbing-resistant membrane material for bioreactor and preparation method of rubbing-resistant membrane material

Abstract

The invention discloses a rubbing-resistant membrane material for a bioreactor and a preparation method of the rubbing-resistant membrane material, and belongs to the technical field of layered products, the rubbing-resistant membrane material has a five-layer structure, and the five-layer structure sequentially comprises an outer layer, an inner layer, an outer layer and an inner layer from outside to inside, the outer layer is made of a mixture of linear low-density polyethylene and ultra-low-density polyethylene, and the thickness of the outer layer is 50-120 microns; the outer bonding layer is made of ultralow-density polyethylene grafted maleic anhydride; the barrier layer is made of ethylene-vinyl alcohol copolymer, and the thickness of the barrier layer is 8-20 microns; the inner bonding layer is made of ultralow-density polyethylene grafted maleic anhydride, and the thickness of the inner bonding layer is 5-10 microns; the inner layer is made of ultra-low-density polyethylene, the thickness of the inner layer is 60-100 microns, the biological membrane material does not need to introduce excessive functional layers, and the rubbing performance can be improved on the premise that the requirements of a bioreactor on barrier, mechanics and the like can be met by adjusting the composition of the inner layer, the bonding layer, the barrier layer and the outer layer.

Description

Technical Field

[0001] This invention belongs to the technical field of membrane materials for bioreactors, specifically relating to a rub-resistant membrane material for bioreactors and its preparation method. Background Technology

[0002] In biopharmaceuticals, cell therapy, and bioengineering, bioreactors serve as core production equipment, and performance upgrades and material innovation are always crucial. As a core component of disposable bioprocess bags, the performance of membrane materials used in bioreactors directly determines the reactor's reliability and applicable scenarios. Multilayer co-extruded membranes, due to their ability to achieve synergistic effects of biocompatibility, gas barrier properties, and mechanical strength through the composite of different functional layers, have become the preferred material type in this field. A typical multilayer co-extruded membrane usually consists of a contact layer (directly in contact with biological media such as cells and culture media), a barrier layer (preventing the permeation of gases such as oxygen and carbon dioxide from affecting the reaction environment), and a support layer (providing mechanical support). These layers are bonded at the interface through a co-extrusion process, forming an integrated structure. However, in practical applications, multilayer co-extruded membrane materials used in bioreactors are prone to problems such as welded structure damage and structural delamination after repeated folding and crumpling, leading to media leakage and a sharp drop in separation efficiency, failing to meet the requirements of scenarios requiring repeated operation and multiple uses.

[0003] In existing technologies, certain cells are not suitable for EVA contact layers; and the bio-bag membrane material of polyethylene contact layers has relatively poor abrasion resistance. Patent 202510716317.3 introduces a flexible support layer into the intermediate layer. This flexible support layer comprises at least two directly connected flexible layers. Each flexible layer includes a random copolymer containing ethylene structural units and unsaturated carboxylic acid ester structural units, and optionally a polyolefin. The Shore A hardness (H) of a single flexible layer is no higher than 90 Shore A, and the hardness of the flexible layer is no higher than that of the barrier layer. Compared to a single flexible layer, the multiple flexible layers in this invention's flexible support layer allow for slight slippage, enabling a higher hardness setting (no higher than 90 Shore A) for each flexible layer. Furthermore, the copolymer in the flexible layer uses ester-grafted polyolefin segments, utilizing branched chains to form a looser intermolecular arrangement, thus giving the flexible layer better flexibility. However, the material of this invention has drawbacks: a more complex structural composition and a more cumbersome processing procedure. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0006] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a membrane material for a rub-resistant bioreactor.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: the membrane material has a five-layer structure, which includes, from the outside to the inside, layers... The outer layer is made of a mixture of linear low-density polyethylene and ultra-low-density polyethylene, with a thickness of 50~120μm; The outer adhesive layer is made of ultra-low density polyethylene grafted with maleic anhydride, with a thickness of 5~10μm.

[0008] The barrier layer is made of ethylene-vinyl alcohol copolymer and has a thickness of 8~20μm. The inner adhesive layer is made of ultra-low density polyethylene grafted with maleic anhydride, with a thickness of 5~10μm. The inner layer is made of ultra-low density polyethylene with a thickness of 60~100μm.

[0009] As a preferred embodiment of the membrane material for the rub-resistant bioreactor described in this invention, the mass ratio of linear low-density polyethylene to ultra-low-density polyethylene in the outer layer is 20:1 to 5:2.

[0010] It should be noted that the addition of ultra-low density polyethylene can improve the flexibility of the outer membrane material. If the content of ultra-low density polyethylene is too low, the improvement in membrane flexibility will not be significant, while if the content is too high, the mechanical properties and temperature resistance will be affected.

[0011] As a preferred embodiment of the membrane material for the rub-resistant bioreactor described in this invention, the outer adhesive layer and the inner adhesive layer are made of ultra-low density polyethylene grafted with maleic anhydride, wherein the ultra-low density polyethylene is inserted with 5-10 mol% of 1-octene, and the content of maleic anhydride is 1.0-3.0 wt%.

[0012] It should be noted that if the 1-octene insertion rate in the adhesive layer is too low, the improvement in flexibility will not be significant; if the octene insertion rate is too high, the strength and melting point will decrease significantly, affecting the strength of the material.

[0013] As a preferred embodiment of the membrane material for the rub-resistant bioreactor described in this invention, the ethylene content of the ethylene-vinyl alcohol copolymer in the barrier layer is 32~38wt%.

[0014] As a preferred embodiment of the membrane material for the rub-resistant bioreactor described in this invention, wherein: 8-15 mol% of 1-octene is inserted into the ultra-low density polyethylene in the inner layer.

[0015] It should be noted that if the insertion rate of 1-octene is too low, the flexibility of the molecular chain segments will be reduced, resulting in poor resistance to tearing of the membrane material. If the insertion rate is too high, the mechanical strength of the inner membrane will decrease and the melting point will be lowered, making it difficult to meet the mechanical requirements of bioreactor membrane materials.

[0016] As a preferred embodiment of the rub-resistant bioreactor membrane material of the present invention, the melt index difference between the layers is <1.0 g / 10 min.

[0017] As a preferred embodiment of the rub-resistant bioreactor membrane material of the present invention, the method for preparing the ultra-low density polyethylene grafted with maleic anhydride includes: Ultra-low density polyethylene, maleic anhydride, and initiator are mixed and continuously reacted, extruded, and granulated at a temperature of 170-190℃ and a speed of 30-50 rpm to obtain ultra-low density polyethylene grafted with maleic anhydride.

[0018] Another object of the present invention is to provide a method for preparing a membrane material for a rub-resistant bioreactor.

[0019] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including, Each functional layer resin raw material is dried and dehydrated under vacuum at 60°C to obtain a dried functional layer resin raw material. The dried functional layer resin raw material is added to the hopper, wherein... The temperature of the raw material inlet of the inner layer resin and each section of the screw is 210~230℃, and the rotation speed is 50~60rpm; The temperature of the raw material inlet and each section of the screw for the barrier layer resin is 225~240℃, and the rotation speed is 10~20rpm. The temperature of the raw material resin inlet of the inner and outer adhesive layers and the temperature of each section of the screw are 210~230℃, and the rotation speed is 8~15rpm; The temperature of the outer layer's raw material resin inlet and each section of the screw is 210~230℃, and the rotation speed is 50~70rpm. The die head temperature is 230~240℃, and the traction and winding process yields a rub-resistant bioreactor membrane material.

[0020] Beneficial effects of this invention: (1) The rub-resistant bioreactor membrane material of the present invention does not require the introduction of too many functional layers. By adjusting the composition of the inner layer, adhesive layer, barrier layer and outer layer, the rub-resistant performance can be improved while meeting the requirements of the bioreactor for barrier, mechanical and other aspects.

[0021] (2) This invention has found that the flexibility of the same material varies greatly if there are differences in its intrinsic structure. In particular, the octene insertion rate in ULDPE has a great influence on the overall performance of the resin, affecting its processing technology, melting point, mechanical strength and flexibility. By optimizing the octene insertion rate, its kneading resistance can be further improved while meeting the mechanical and temperature resistance requirements of bioreactors and other applications.

[0022] (3) The present invention selects ULDPE as the base material of the adhesive layer. It has uniform short branches and more uniform distribution of active points, making it easier to achieve uniform grafting. This not only improves the bonding strength between ULDPE and EVOH, but also retains the high flexibility of ULDPE. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 The infrared spectrum of ULDPE-g-MAH prepared in Example 1 of this invention is shown.

[0024] Figure 2 This is a schematic diagram of the structure of the rub-resistant bioreactor membrane material of the present invention.

[0025] Figure 3 This is a DSC curve of the membrane material prepared in Example 1 of the present invention. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0029] Unless otherwise specified, all raw materials used in this invention are commercially available in the art. Specifically: ULDPE refers to Dow Chemical's ENGAGE and ATTANE series, such as 8402, 8440, 8107, 8450, 8003, 8100 and 8180, 4203 and 4201; ULDPEs with different octene insertion rates were obtained by selecting different grades of the ENGAGE series products; LLDPE and LDPE grades include, but are not limited to, Dow 20 Health+ Ultra pure PE, Sabic LDPEPCG22, Sabic LDPE PCG22, Dow LDPE 692 Health+, and Bormed LE6607-PH; EVOH is H101B, H171B, C109B, J171B, Taiwan Changchun EV3201F, EV3201V.

[0030] The properties of the membrane material obtained by this invention were tested using the following methods: Tensile strength shall be determined in accordance with GB / T 1040.3 Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets; The oxygen transmission rate test shall be conducted according to GB / T 1038-2000 Test Method for Gas Permeability of Plastic Films and Sheets; The rubbing resistance is determined by the test method of GJB 2589.6-1996, "Test Method for Physical and Chemical Properties of Military Leather and Fur". The material is deemed to have failed when delamination, damage, light transmission points or ink leakage are found after a certain number of flexing cycles.

[0031] Example 1 Reference Figures 1-3 This embodiment provides a rub-resistant bioreactor membrane material and its preparation method, specifically: 1) Preparation of maleic anhydride grafted onto ultra-low density polyethylene: Ultra-low density polyethylene (ULDPE, Dow ENGAGE 8402, 1-octene insertion rate 5.0 mol%), maleic anhydride (MAH) and dicumyl peroxide (DCP) initiator were thoroughly mixed in a high-speed mixer at a mass ratio of 100:2:0.5. The uniformly mixed material is fed into a twin-screw extruder. The temperatures of each section of the extruder are set as follows: Zone 1 170℃, Zone 2 175℃, Zone 3 180℃, Zone 4 185℃, and the die head 190℃. The screw speed is set to 40 rpm. After the extruded material undergoes melt reaction, extrusion, water cooling, and pelletizing, ULDPE-g-MAH graft copolymer particles are obtained. Figure 1The infrared spectrum of ULDPE-g-MAH was measured at 1791 cm⁻¹. -1 The presence of a characteristic peak of MAH at the point indicates successful grafting, with a MAH grafting rate of 2.0 wt%.

[0032] In subsequent embodiments, the grafting rate of MAH can be controlled by adjusting the ratio of MAH to ULDPE.

[0033] 2) such as Figure 2 The diagram shows the structure of a rub-resistant bioreactor membrane. The rub-resistant bioreactor membrane has a five-layer structure, from the outside in: The outer layer is made of a mixture of low-density polyethylene (LLDPE, Dow 20 Health+ Ultra pure PE, melt index 1.9 g / 10 min) and ultra-low-density polyethylene (ULDPE, Dow ENGAGE 8003, 1-octene insertion rate 10 mol%, melt index 1.0 g / 10 min) in a mass ratio of 10:1, and the outer layer thickness is 50 μm. The outer adhesive layer is made of ultra-low density polyethylene grafted maleic anhydride (ULDPE-g-MAH), where ULDPE is Dow ENGAGE 8107, the 1-octene insertion rate is 7 mol%, the grafted maleic anhydride (MAH) content is 2.0 wt%, and the outer adhesive layer thickness is 8 μm.

[0034] The barrier layer is made of ethylene-vinyl alcohol copolymer (EVOH, Kuraray J171B), with an ethylene content of 32wt%, a melt index of 1.7g / 10min, and a barrier layer thickness of 15μm. The inner adhesive layer is made of ultra-low density polyethylene grafted maleic anhydride (ULDPE-g-MAH), where ULDPE is Dow ENGAGE 8107, the 1-octene insertion rate is 7 mol%, the grafted maleic anhydride (MAH) content is 2.0 wt%, and the thickness of the inner adhesive layer is 8 μm. The inner layer is made of ultra-low density polyethylene (ULDPE, Dow Engage 8440), with a 1-octene insertion rate of 12 mol% and a melt index of 1.0 g / 10 min. The inner layer thickness is 60 μm. 3) Preparation of tear-resistant bioreactor membranes: The raw material resins of each layer (LLDPE, ULDPE, self-made ULDPE-g-MAH, EVOH) were dried in a vacuum oven at 60°C for 6 hours to remove moisture; Bioreactor membrane materials were prepared using a multi-layer co-extrusion device, with each dried resin being added to its corresponding feed hopper: Inner layer: ULDPE (Dow ENGAGE 8440, 1-octene insertion rate 12mol%), feed port and screw section temperature set at 220℃, screw speed at 55rpm.

[0035] Inner / outer adhesive layer: self-made ULDPE-g-MAH, with the temperature of the feed inlet and each section of the screw set at 220℃ and the screw speed at 12rpm.

[0036] Barrier layer: EVOH (Kuraray J171B, ethylene content 32%), feed inlet and screw section temperature set at 235℃, screw speed at 15rpm.

[0037] Outer layer: LLDPE / ULDPE (10:1) mixture, the temperature of the feed inlet and each section of the screw is set to 220℃, and the screw speed is 60rpm.

[0038] The die head temperature is uniformly set to 235℃. By precisely adjusting the traction speed, the final membrane material thickness is controlled within the range of 140±5μm. After winding, a tear-resistant bioreactor membrane material is obtained. Figure 3 The image shows the DSC curve of the membrane material prepared in this embodiment. The melting point of 95.39℃ corresponds to ULDPE, 112.98℃ corresponds to LDPE, and 194.92℃ corresponds to EVOH, which proves that the material was successfully prepared.

[0039] Example 2 The difference between this embodiment and Example 1 is that the 1-octene insertion rate of the inner layer material, ultra-low density polyethylene, was adjusted to 0 (SABIC® LLDPE 118NJ), 8 mol% (Dow ENGAGE 8480), 10 mol% (Dow ENGAGE 8450), 12 mol% (Dow ENGAGE 8440, Example 1), 15 mol% (Dow ENGAGE 8003), and 20 mol% (Dow ENGAGE 8100). The remaining raw material steps and processes were the same as in Example 1, resulting in the bioreactor membrane material of this embodiment.

[0040] The performance of the bioreactor membrane material prepared by the inner layer material with different 1-octene insertion rates in this embodiment was determined, and the results are shown in Table 1.

[0041] Table 1

[0042] As shown in Table 1, with the same thickness, as the insertion rate of 1-octene in the inner ULDPE increases, the melting point of ULDPE decreases and the number of tumble cycles increases. Considering actual usage, when the octene insertion rate is 20 mol%, the melting point of the membrane material is only 59.8℃. The temperature setting during processing is too different from that of other functional layers, which leads to poor adhesion and a decrease in tumble resistance. Therefore, the optimal octene insertion rate is 8~15 mol%.

[0043] Example 3 The difference between this embodiment and Example 1 is that the inner layer thickness is adjusted to 40μm, 60μm (Example 1), 80μm, 100μm, and 150μm respectively. The remaining raw material steps and processes are the same as in Example 1, and the bioreactor membrane material of this embodiment is obtained.

[0044] The performance of the bioreactor membrane materials prepared with different inner layer thicknesses in this embodiment was measured, and the results are shown in Table 2.

[0045] Table 2

[0046] As can be seen from Table 2, under the condition of consistent inner layer structure, there is an optimal range for inner layer thickness (60~100μm). If the inner layer is too thin, it is difficult to provide flexibility for the entire membrane material; if the inner layer is too thick, it is easy to form an angle during bending and kneading, resulting in stress concentration and a decrease in the material's kneading performance.

[0047] Example 4 The difference between this embodiment and Example 1 is that the mass ratio of linear low-density polyethylene to ultra-low-density polyethylene in the outer layer material is adjusted to 10:0, 20:1, 10:1 (Example 1), 5:1, 5:2, and 1:1, respectively. The remaining raw material steps and processes are the same as in Example 1, thus obtaining the bioreactor membrane material of this embodiment.

[0048] The performance of bioreactor membrane materials prepared with different outer layer material composition ratios in this embodiment was determined, and the results are shown in Table 3.

[0049] Table 3

[0050] As can be seen from Table 3, with the same outer layer thickness, the tensile strength of the membrane material decreases and the rub resistance increases with the increase of ULDPE content. However, if the ULDPE content exceeds a certain range, it will have a significant impact on the temperature resistance and mechanical properties of the material. Therefore, considering practical applications, the optimal mass ratio of LLDPE to ULDPE is in the range of 20:1 to 5:2.

[0051] Example 5 The difference between this embodiment and Example 1 is that the outer layer thickness is adjusted to 50μm (Example 1), 80μm, 100μm, and 120μm respectively. The remaining raw material steps and processes are the same as in Example 1, and the bioreactor membrane material of this embodiment is obtained.

[0052] The performance of the bioreactor membrane materials prepared with different outer layer thicknesses in this embodiment was measured, and the results are shown in Table 4.

[0053] Table 4

[0054] As can be seen from Table 4, the mechanical properties of the material do not change much with the increase of the outer layer thickness, but the number of tumbling cycles first increases and then decreases. Therefore, the thickness is best in the range of 50~120μm.

[0055] Example 6 The difference between this embodiment and Example 1 is that the 1-octene insertion rate of ULDPE in the low-density polyethylene grafted maleic anhydride (ULDPE-g-MAH) material of the inner and outer adhesive layers was adjusted to 0 mol% (SABIC® LLDPE 118NJ), 5 mol% (Dow ENGAGE 8402), 7 mol% (Dow ENGAGE 8440, Example 1), 10 mol% (Dow ENGAGE 8450), and 20 mol% (Dow ENGAGE 8100), respectively, and the MAH grafting rate was 1.0%, 2.0% (Example 1), and 3.0%, respectively. The remaining raw material steps and processes were the same as in Example 1, and the bioreactor membrane material of this embodiment was obtained.

[0056] The performance of bioreactor membrane materials prepared by adhesive layer materials with different 1-octene insertion rates in this embodiment was measured, and the results are shown in Table 5.

[0057] Table 5

[0058] As shown in Table 5, the higher the octene insertion rate and MAH grafting rate, the more the material's tumbling resistance increased and then decreased. This is mainly because the higher the octene insertion rate, the lower the molecular chain regularity of the adhesive layer resin and the greater its flexibility. It also provides more grafting sites for MAH. A moderate MAH grafting rate can provide higher adhesion. When the MAH grafting rate exceeds a certain range, excessive cross-linking will occur, leading to a decrease in the adhesion performance of each layer, which in turn affects the tumbling resistance.

[0059] Example 7 The difference between this embodiment and Example 1 is that the thicknesses of the inner and outer adhesive layers are adjusted to 5μm, 8μm (Example 1), and 10μm, respectively. The remaining raw material steps and processes are the same as in Example 1, thus obtaining the bioreactor membrane material of this embodiment.

[0060] The performance of the bioreactor membrane materials prepared with different adhesive layer thicknesses in this embodiment was measured, and the results are shown in Table 6.

[0061] Table 6

[0062] As can be seen from Table 6, the tumbling resistance of the material is improved to a certain extent with the increase of the adhesive layer thickness. However, if the thickness exceeds a certain limit, stress concentration will also occur. Therefore, the preferred range for the thickness of the adhesive layer is 5~10μm.

[0063] Example 8 The difference between this embodiment and Example 1 is that the ethylene content in the ethylene-vinyl alcohol copolymer EVOH of the barrier layer material is adjusted to 27wt% (Kuraray L171), 32wt% (Kuraray J171B), 35wt% (Kuraray C109), 38wt% (Kuraray H171B), and 44wt% (E105), respectively. The remaining raw material steps and processes are the same as in Example 1, thus obtaining the bioreactor membrane material of this embodiment.

[0064] The performance of the bioreactor membrane materials prepared with different ethylene content barrier layer materials in this embodiment was measured, and the results are shown in Table 7.

[0065] Table 7

[0066] As shown in Table 7, with the increase of ethylene content in EVOH, the tensile strength of the membrane material decreases to some extent, while the number of tumbling cycles increases. This is mainly because the decrease in the number of vinyl alcohol segments that aggregate and crystallize through hydrogen bonding in EVOH leads to increased resin flexibility. Similarly, this is also a major reason for the increase in oxygen permeability of the material. Given the oxygen barrier performance requirements of bioreactors, the ethylene content in EVOH is preferably 32-38%.

[0067] Example 9 The difference between this embodiment and Example 1 is that the thickness of the barrier layer is adjusted to 4μm, 8μm, 15μm (Example 1), 20μm, and 30μm respectively, while the remaining raw material steps and processes are the same as in Example 1, to obtain the bioreactor membrane material of this embodiment.

[0068] The performance of the bioreactor membrane materials prepared with different barrier layer thicknesses in this embodiment was measured, and the results are shown in Table 8.

[0069] Table 8

[0070] As can be seen from Table 8, the tumbling resistance of the material decreases with the increase of the barrier layer thickness. Considering the oxygen permeability requirements, the preferred thickness of the barrier layer is 8~20μm.

[0071] Comparative Example 1 The difference between this comparative example and Example 1 is that the material of the outer layer is adjusted to be high-density polyethylene (HDPE, Rakuten HIVOREX® 5000S), while the remaining steps and processes are the same as in Example 1, to obtain the bioreactor membrane material of this comparative example.

[0072] Comparative Example 2 The difference from Example 1 is that the material of the barrier layer was adjusted to be polyamide 66 (PA6, Durethan® B30S000000), and the remaining steps and processes were the same as in Example 1, to obtain the bioreactor membrane material of this comparative example.

[0073] Comparative Example 3 The difference from Example 1 is that the material of the inner and outer adhesive layers is adjusted to be high-density polyethylene grafted with maleic anhydride (HDPE-g-MAH), and the remaining steps and processes are the same as in Example 1, so as to obtain the bioreactor membrane material of this comparative example.

[0074] Comparative Example 4 The difference from Example 1 is that the inner layer material is adjusted to high-density polyethylene (HDPE), while the remaining steps and processes are the same as in Example 1, to obtain the bioreactor membrane material of this comparative example.

[0075] The relevant properties of the bioreactor membrane materials of Comparative Examples 1 to 4 were measured and compared with those of Example 1. The results are shown in Table 9.

[0076] Table 9

[0077] As shown in Table 9, HDPE as an inner or outer layer can improve the tensile strength of the membrane material, but its rub resistance decreases significantly. At the same time, grafting it with MAH as an adhesive layer can also improve the tensile strength of the material to a certain extent. However, due to the poor flexibility of the adhesive layer, stress concentration is easily generated during repeated rubbing and bending, leading to delamination and cracking. PA66 as a gas barrier layer can improve the rub resistance and tensile strength of the material to a certain extent, but its oxygen permeability is too high.

[0078] In summary, the biofilm material of the present invention does not require the introduction of too many functional layers. By adjusting the composition of the inner layer, adhesive layer, barrier layer and outer layer, the requirements of bioreactors for barrier, mechanical and other properties can be met, thereby improving the resistance to kneading.

[0079] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A mar- and wrinkle- resistant membrane material for bioreactors, characterized by: The film material has a five-layer structure, from outside to inside, comprising, an outer layer, the material is a mixture of linear low density polyethylene and ultra low density polyethylene, the thickness is 50-120μm; an outer adhesive layer, the material is ultra low density polyethylene grafted maleic anhydride, the thickness is 5-10μm. a barrier layer, the material is ethylene-vinyl alcohol copolymer, the thickness is 8-20μm; an inner adhesive layer, the material is ultra low density polyethylene grafted maleic anhydride, the thickness is 5-10μm; an inner layer, the material is ultra low density polyethylene, the thickness is 60-100μm.

2. The abrasion resistant bioreactor membrane material of claim 1, wherein: The mass ratio of linear low density polyethylene to ultra low density polyethylene in the outer layer is 20:1-5:

2.

3. The abrasion resistant bioreactor membrane material of claim 1, wherein: The material of the outer adhesive layer and the inner adhesive layer is ultra low density polyethylene grafted maleic anhydride, wherein the ultra low density polyethylene is inserted with 5-10mol% 1-octene, and the content of maleic anhydride is 1.0-3.0wt%.

4. The abrasion resistant membrane material for bioreactors of claim 1, wherein: The content of ethylene in the ethylene-vinyl alcohol copolymer in the barrier layer is 32-38wt%.

5. The mar- and abrasion- resistant membrane material for bioreactors of claim 1, wherein: The ultra low density polyethylene in the inner layer is inserted with 8-15mol% 1-octene.

6. The abrasion resistant bioreactor membrane material according to any one of claims 1 to 5, wherein: The difference of the melt index between the materials of each layer is <1.0g / 10min.

7. The mar- and abrasion- resistant membrane material for bioreactors of claim 3, wherein: The preparation method of the ultra low density polyethylene grafted maleic anhydride comprises, mixing the ultra low density polyethylene, maleic anhydride and initiator at a temperature of 170-190℃ and a rate of 30-50rpm, continuously reacting, extruding and granulating to obtain the ultra low density polyethylene grafted maleic anhydride.

8. The method of making a mar- and abrasion- resistant bioreactor membrane material according to any one of claims 1 to 5 or 7, wherein: comprising, drying the functional layer resin raw materials at 60℃ under vacuum to obtain dried functional layer resin raw materials; adding the dried functional layer resin raw materials into the hopper, wherein, the temperature of the raw material feeding port and the screw of the inner layer resin is 210-230℃, and the rotation speed is 50-60rpm; the temperature of the raw material feeding port and the screw of the barrier layer resin is 225-240℃, and the rotation speed is 10-20rpm; the temperature of the raw material feeding port and the screw of the inner adhesive layer and the outer adhesive layer is 210-230℃, and the rotation speed is 8-15rpm; the temperature of the raw material feeding port and the screw of the outer layer is 210-230℃, and the rotation speed is 50-70rpm; the die temperature is 230-240℃, and the film material is obtained by pulling and winding.

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